My friend has asked me to look around for a utility that can encrypt an entire hard drive. The hard drive will be used only with one machine, but there are 3 users on it, and he only wants himself to be able to access the drive. Is there a program out there that will encrypt an entire hard drive so that it requires a password to either mount it or access files?
remember, this hard drive will not be moved to another machine, so if something actually has to be installed into the system, that would be fine.

what about the built in (if it's running 10.3 or 10.4) filevault? it's under the security panel in system preferences. It sounds like that would do everything you would need. I used to use it, but since i'm running on a 400mhz G3, it really became a bottleneck, so I disabled it. Still, if you have the power, use it. it's a very nice system.

I don't think it's a bug. it makes a copy of the home folder, so you would need enough space as the home folder is big. Sorry, but i have never used anything but filevault. it's very secure, but it takes space.

He could use an encrypted disk image, but I doubt that would satisfy any kind of tinfoil hattery, so I suggest looking into using PGP to encrypt an entire hard disk. It won't work for the boot disk, but it works on any other disk, is 'transparent', and the encrypted disk format is compatable with Windows and Mac OS. It looks like you can download it from here.